Process and apparatus for making artificial filaments



Sept. 11, 1934.

C. DREYFUS ET AL PROCESS AND APPARATUS FOR MAKING ARTIFICIAL FILAMENTSFiled Sept. 8. 1928' VIIIIIIIIIIIIIIIIIIIIIIIII I/II/Y/IIIIIIIIIIIII/IINVENTORS CAMILLE DREYFUS WILLIAM WHITEHEAD QEVWM ATTORNEYS PatentedSept. 11, 1934 UNITED STATES v mus c PROCESS AND APPARATUS FOR MAKINGARTIFICIAL FILAMENTS Camille Dreyfus, New York, N. Y., and WilliamWhitehead, Cumberland, Md.,

assignors to Celanese Corporation of America, a corporation of DelawareApplication September 8, 1928, Serial No. 304,807

11 Claims.

heavy artificial filaments in such a manner that breakage of thefilaments during their formation 5 owing to their weight is avoided.Other objects of our invention will appear from the following detaileddescription.

The formation of comparatively heavy filaments such as bristles and thelike for use in brushes by the dry spinning method has heretoforeoffered serious difficulty. This is due to the fact that as the solutionof the cellulose derivative is extruded through the orifices of aspinnerette into the evaporative atmosphere, the filaments near the jetare not sufiiciently strong to support the weight of the filaments,because of the fact that the filaments in the ordinary process are driedwhile suspended vertically for a substantial distance from thespinnerette, with the result that they break and continuous spinning isnot possible. We have found that if the filaments are supported near thespinnerette, continuous spinning is possible.

In accordance with our invention, we prepare filaments from solutions oforganic derivatives of cellulose. The solutions are made by dissolvingthe organic derivative of cellulose in a suitable solvent or solventmixture to form solutions of suitable concentration. The solution may ormay not be filtered and is then forced through orifices of a spinneretteof suitable size into the metier or casing of a dry spinning machinewherein'a heated evaporative atmosphere is caused to flow. 1 Within thespinning chamber, there is placed a suitable feed device positioned inclose proximity to the spinnerette so as to support the weight ofthefilafilaments are formed. These heavier filaments may be in the formof bristles of 20 to 2000 denier or more for use in hair brushes,clothes brushes, nail brushes, sweeping brushes, scrubbing brushes orthe like. Bristlesior use in making braids and. the like may also bemade by our process. The filaments to be formed may be in the formof'fiat filaments for use as artificial straw in making of hats,trimmings, weaving of baskets, etc. Also other films may be formed byour invention. An-' other use of our process is for the making .of'artificial hair for use in making artificial fur and for other purposes.The organic derivative of cellulose that may be. employed-in our processmay be organic esters of cellulose or cellulose ethers. Examples oforganic esters are cellulose acetate, cellulose formate, cellulosepropionate and cellulose butyrate, While examples of cellulose othersare ethyl cellulose, methyl cellulose and benzyl cellulosec The organicderivatives of cellulose may be dissolved in any suitable solvent formaking the spinning solutions. An example of av suitable solvent isacetone or mixtures of acetone. and water varying in proportions from 90parts 'of ace tonev to 10 parts of water, to 78 parts of acetone to 22parts of water. Mixtures of acetone and ethyl or methyl alcohol in likeproportions may also be used as the solvent. Examplesoi othersolvents-are ethylene dichloride, ethylene dichloride and ethyl ormethyl alcohol, chloroform, chloroform and ethyl or methylalcohol,-methyl-'-" ene chloride and ethyl or methyl alcohol. Thesolutions maybe'made of any suitable concentra tion say 10 to 40% byweight of the organic-deriv ative of cellulose of the totalweightofi'the -solution. As stated before, the solution may or may 'notbe filtered. When heavy filaments are formed, filtering is notabsolutely necessary since the holes employed in the spinnerette arecomparatively large. However, if desired, the solution may be filteredby hydraulic pressure or pump pressure, through filter presses or otherfiltering devices. j 1

Any suitable-gas may be used as an evapora-- tive atmosphere in thespinning machine, "examples of which are air,-nitrogen, carbon dioxide,or other gas that has no detrimental action on the products produced.The atmosphere is preferably heated to about the boiling point of thesolvent mixture, althoughtemperatures be-] low or above the boilingpoint of the solvent'mix ture may be employed advantageously.

- The filaments formed are taken up bya suitable feeding device whichmaybe 'inthe form of a roll, wheel, belt-like conveyor, etc., rotatingor moving in such a manner as 'to-wind oif and/or draw out the filamentunder formation. Thefilament is caused to pass over or around suchdevice, and may be gathered up and wound into suitable packages, such asbobbins, hanks, cones, etc. The feed device is placed in close proximityto the spinning jet, but it should be suificiently distant therefrom sothat the filament does not adhere strongly to the jet. However, the feeddevice should be positioned at a distance that is not so great that theunsupported length of the filament is so heavy as to cause breaking offof the same at the jet. We have found that the filaments drysufficiently within a short distance of the jet. As an example, it maybe stated that in the spinning of heavy bristles or straws of say 250 to2000 denier, While employing a spinning temperature of about the boilingpoint of the solvent or slightly less (e.,g. 10 C.) and with a feed rateof 50 meters of length of filament per minute, the feeding device may beset from 1 to 3 feet from the spinnerette, depending on the solventemployed and the concentration of the spinning solution.

The feed device need not necessarily be placed so that its first contactwith the filament is vertically or approximately so under the spinningjet. The feed device may be placed obliquely from the spinning jet, ormay be even placed in the same horizontal plane with the jet. Where atensional pull on the filament under formation is required between thespinnerette and the feed devices, the jet should be directed towards thefeed device.

The feed device may be heated by any desired method such as byelectrical resistances, steam (dry, superheated, or under pressure) hotliquids or gases to assist the further drying of the filaments.

We have found that on drying, the filamentstend to contract in length aswell as in diameter, and that if two or more feed devices are used,which operate so-as to feed the filaments at the same linear velocity,the contraction in length of the filaments on drying between two or morefeed devices is prevented. We have found the surprising fact that theresulting product is stronger than would have been the case if the.tfilaments had been permitted to contract .in length. Further gains instrength maybe obtained if the feed devices are caused to feed thefilament at successively greater speed, drawing it out to a finer sizeas it dries between such feed devices. For example, the filament may bepassed over or around three rolls successively, the first being 18" fromthe spinning jet, the sec- 0nd 1 it. from the first and the third, one'foot from the second. The first roller may be rotated at a rate to drawthe filament at 20 meters per minute, the second at 22 meters per minuteand the third at 23 meters per minute.

By way of illustration of a process wherein three rolls are employed,the following is given. A spinning solution, consisting of one part ofan acetone soluble cellulose acetate in 3 parts of asolvent mixturecomprising of acetone and 10% of water, is spun through a round hole of0.4 mm. in diameter. The solution is so extruded from the jet and thefirst roll is rotated at such.

a rate as to produce a bristle-like fiber of 400 denier. By rotating'thesecond and third roller at successively higher speeds, a bristle. of 348denier is formed, which has a breaking strength approximately equal tothat of a bristle of 400 denier that is spun with the use of only onefeed roll. A bristle of 348 denier spun with the use of only one rollerhas a breaking strength of approximately 348/400 of that of a 400 denierbristle spun in like manner. Corresponding increases of strength areobserved when finer filaments, such as are used in making artificialsilks, are formed. It will be noted that in our process where two ormore rollers are employed, the filaments are drawn between the feedingdevices while they still contain appreciable amounts of solvent.

In order further to illustrate our invention, reference is had to theaccompanying drawing, where examples of suitable devices are showndiagrammatical. In the drawing,

Fig. 1 is a diagrammatical view of a spinning machine embodying one formof our invention,

Fig. 2 is a similar View of another embodiment of our invention,

Fig. 3 is a similar view of still another form of our invention,

Fig. 4 is a similar view of still another form of our invention, and

Fig. 5 is a similar View of still another form of our invention.

Referring to all of the figures, 1 represents a metier or casing of adry spinning machine for the spinning of filaments from solutions of thecellulose derivative. In this metier l, a heated atmosphere is caused toflow. The solution of organic derivative of cellulose in a volatilesolvent is extruded through the orifices of the spinnerette 2, and thestream of organic derivative of cellulose is caused to assume the formera filament generally indicated at 3.

In the form shown in Fig. 1, the filament '3 passes from the spinneretteto vertically down to a feed roll 4 which'is placed at a short distancebelow the spinnerette 2. The filament 3 passes around the roll 4 underthe guide roll 5 to the feed roll 6 and thence to the winding device 7.

In the form shown in Fig. 2, the filament 3 passes from thespinnerette 2vertically down be tween the rolls 10 and 11 which are rotating inopposite directions in light contact with each other. The filament thussupported and drawn from the spinnerette and is caused to pass underaround the feed roll 20, under the guide roll 21 and is wound into asuitable package by the winding device 22.

In Fig. 4, the feed roll 30 is placed laterally of the spinnerette 2,and the filament 3 is permitted to loop at 31 between the spinneretteand the feed roll. The filament passes around the roll 30, under theguide roll 32 to a winding device 33.

In Fig. 5, a modification is shown wherein the filament under formationis passed through the spinning chamber by means of a plurality offeeding devices. The filament 3 passes from the spinnerette 2, aroundthe feed roll 40, then around 1.:

thefeed roll 41, then around the feed roll 42, and then around the feedroll 43, out of the metier casing 1 to the winding device 44. The rolls40, 41, 42 and 43 may be rotated at the same speed or at progressivelygreater speeds in order to obtain 3 filaments of increased. strength asexplained above. Instead of employing only one drying chamber, thefilamentmay be passed to a plurality of drying chambers having feeddevices, if so desired.

It is to be understood that the foregoing detailed description is givenmerely by way of illustration and that many variations may be madetherein without departing from the spirit of our invention.

Having described our invention what we claim and desire to secure byLetters Patent is:

1. Method of forming articles such as filaments, yarns, bristles, filmsand the like comprising extruding a solution of an organic derivative ofcellulose in a volatile solvent through orifices into a heatedevaporative atmosphere and relieving the weight of the articles formedby resting the same on a feeding device placed in proximity to saidorifices, said feeding device rotating at such a speed as to preventlinear shrinkage of the articles.

2. In a dry spinning machine the combination of a casing through which aheated evaporative atmosphere is adapted to flow, a spinnerette havingan orifice therein through which a spinning solution is adaptedto fiow,a feed device positioned within said casing in close proximity to saidorifice and adapted to support the newly formed filamentary material,another feed device within said casing adapted to move at a speed atleast equal to the first feed device, and adapted to carry the filamentfrom the first feed device.

3. Method of forming articles such as filaments, yarns, bristles, filmsand the like comprising extruding a solution of cellulose acetate in avolatile solvent through orifices into a heated evaporative atmosphereand relieving the extruded solution of at least part of the weight ofthe articles formed by resting the same on a feeding device placed inproximity to said orifices and in the evaporative atmosphere, saidfeeding device rotating at such a speed as to prevent linear shrinkageof the articles.

4. Method of forming articles such as filaments, yarns, bristles, filmsand the like comprising extruding a solution of an organic derivative ofcellulose in a volatile solvent through an orifice into a heatedevaporative atmosphere and conveying the yarn by means of a roll nearsaid orifice and in the evaporative atmosphere, said roll rotating atsuch a speed as to prevent linear shrinkage of the articles.

5. Method of forming articles such as filamerits, yarns, bristles, filmsand the like comprising extruding a solution of cellulose acetate in avolatile solvent through an orifice into a heated evaporative atmosphereand conveying the yarn by means of a roll near said orifice and in theevaporative atmosphere, said roll rotating at such a speed as to preventlinear shrinkage of the articles.

6. In a dry spinning machine the combination of a casing through which aheated evaporative atmosphere is adapted to fiow, a spinnerette havingan orifice therein through which a spinning solution is adapted to flow,a feed device positioned within said casing in close proximity to saidorifice and adapted to support the newly formed filamentary material,another feed device within said casing adapted to carry the filamentsfrom the first feed device, and means to move the second named feeddevice at a speed greater than that of the first feed device.

'7. In a dry spinning machine the combination of a casing through whicha heated evaporative atmosphere is adapted to flow, a spinnerette havingan orifice therein through which a spinning solution is adapted to flow,a roll positioned within said casing in close proximity to said orificeand adapted to support the newly formed filamentary material, anotherroll within said casing adapted to carry the filaments from the firstroll and means for moving the second named roll at a speed greater thanthat of the first roll.

8. Method of forming filaments or films com prising extruding a solutionof an organic derivative of cellulose through orifices into a heatedevaporative atmosphere, taking up the filaments or films thus formedfrom said orifices on a feed device positioned in close proximity tosaid orifices and adapted to support the newlyformed extruded productsandconveying them to another feed device moving at a speed greater thanthat of the first feed device, while said filaments or films contain anappreciable amount of solvent.

9. Method of forming filaments or films comprising extruding a solutionofcellulose acetate through orifices into'a heated evaporativeatmosphere, taking up the filaments or films thus formed from saidorifices on a feed device positioned in close proximity to said orificesand adapted to support thenewly formed extruded products and conveyingthem to another feed device moving at a speed greater than that of thefirst feed device, while said filaments or films contain an appreciableamount of solvent.

10. Method of forming artificial horsehair, bristles and likefilamentary material of high denier which comprises extruding a solutionof organic derivatives of cellulose through orifices into a heatedevaporative atmosphere, supporting the filamentary materialsubstantially immediately after the formation thereof upon a rotatablesurface and conveying said material to another CAMILLE DREYFUS. WILLIAMWHITEI-IEAD.

